Heretofore, in a beverage dispenser which supplies a beverage to a cup and the like, a syrup supply line is drawn from a tank filled with a syrup as a beverage material, and a diluting water supply line is also disposed which dilutes the syrup at a predetermined ratio. In these syrup supply line and diluting water supply line, a syrup cooling coil and a diluting water cooling coil are interposed, respectively. These coils are immersed into a water tank in which cooling water is stored to cool the syrup and the diluting water flowing through the coils at a predetermined temperature. In consequence, the syrup and the diluting water cooled at the predetermined cooling temperature are mixed at nozzles, respectively, and discharged as a targeted beverage to the cup.
The beverage supplied by the above-mentioned constitution is all stored in the cup in a liquid state. Therefore, ice pieces are separately put into the cup to serve the beverage to a customer in a state in which the beverage can be maintained at a constant cooling temperature for a certain degree of time.
However, when the ice pieces are supplied to the cup, the only beverage around the floating ice pieces is cooled owing to heat of fusion. Therefore, it is difficult to uniformly cool the whole beverage in the cup. Moreover, as the ice pieces melt, concentration of the beverage decreases. It has therefore been difficult to serve the beverage in an appropriately cooled state.
To solve the problem, heretofore, a device including a beverage supercooling heat exchanger constituting a heat pump circuit (a refrigerant circuit) together with a water tank cooling heat exchanger which cools the cooling water stored in the water tank has been developed. The beverage cooled in the water tank is cooled at a temperature of or below a solidifying point of the beverage by the beverage supercooling heat exchanger, and the beverage is discharged to the cup as it is in a supercooled state to serve a sherbet-like beverage (see Patent Japanese Patent Application Laid-Open No. 2001-325656).
In this device, a flow rate of the beverage is controlled to discharge the beverage from the beverage supercooling heat exchanger while maintaining the beverage in a liquid-phase state even at the temperature which is not more than the ice point. Moreover, the beverage is momentarily phase-changed to ice owing to impact at a time when the beverage is discharged to the cup and the like. In consequence, the sherbet-like beverage having fluidity is supplied into the cup.